Recycling of Anhydride-Cured Epoxy Resin Through Alcoholysis and Its Insulation Property after Re-Preparation

Anhydride-cured epoxy resin (ACER) has excellent performance and is commonly employed as insulation material in power equipment. However, it is difficult to decompose and recycle epoxy resin owing to its threedimensional network structure, and conventional waste disposal processes would damage the environment. Hence, it is necessary to degrade or even recycle epoxy resin by other methods. In this paper, chemical degradation of ACER by alcoholysis reaction is realized under mild conditions, and the degraded epoxy resin (DER) is utilized to replace part bisphenol A (BPA) to prepare new epoxy resins. Additionally, the effect of DER content on the dielectric property of re-prepared epoxy resin (resistivity, relative permittivity, dielectric loss, and AC breakdown strength) is studied. Meanwhile, ab-initio calculations on the electrostatic potential, dipole moment and energy level distribution are calculated on the alcoholysis products. The results indicate that when the content of DER replacing BPA is less than 15 wt%, the re-prepared epoxy resin still maintains excellent insulation property. The ester group in the smallmolecule product has electronegativity and induces trap level in the electron band structure, which can be regarded as a “voltage stabilizer”. The recycling of epoxy resin is accomplished through this technology, which can save carbon emissions and benefit the ambient.